Update prog-trans-ts-sdk.md (MystenLabs#9623)

## Description 

Describe the changes or additions included in this PR.

## Test Plan 

How did you test the new or updated feature?

---
If your changes are not user-facing and not a breaking change, you can
skip the following section. Otherwise, please indicate what changed, and
then add to the Release Notes section as highlighted during the release
process.

### Type of Change (Check all that apply)

- [ ] user-visible impact
- [ ] breaking change for a client SDKs
- [ ] breaking change for FNs (FN binary must upgrade)
- [ ] breaking change for validators or node operators (must upgrade
binaries)
- [ ] breaking change for on-chain data layout
- [ ] necessitate either a data wipe or data migration

### Release notes

---------

Co-authored-by: Todd Nowacki <[email protected]>

doc/src/build/prog-trans-ts-sdk.md

@@ -56,7 +56,7 @@ signer.signAndExecuteTransaction({ transaction: tx });
 
 Programmable Transactions have two key concepts: inputs and commands.
 
-Inputs are values that are used as arguments to the commands in the transaction. Inputs can either be an object reference (either to an owned object, or a shared object), or a pure BCS value (for example, an encoded string used as an argument to a move call).
+Inputs are values that are used as arguments to the commands in the transaction. Inputs can either be an object reference (either to an owned object, an immutable object, or a shared object), or a pure BCS value (for example, an encoded string used as an argument to a move call).
 
 Commands are steps of execution in the transaction. You can also use the result of previous commands as arguments to a future command. By combining multiple commands together, programmable transactions provide a flexible way to create complex transactions.
 
@@ -77,7 +77,7 @@ The following commands are available:
     - Example: `tx.mergeCoins(tx.object(coin1), [tx.object(coin2), tx.object(coin3)])`
 - `tx.transferObjects(objects, address)` - Transfers a list of objects to the specified address.
     - Example: `tx.transferObjects([tx.object(thing1), tx.object(thing2)], tx.pure(myAddress))`
-- `tx.moveCall({ target, arguments, typeArguments  })` - Executes a move call. Returns whatever the move call returns.
+- `tx.moveCall({ target, arguments, typeArguments  })` - Executes a move call. Returns whatever the Sui Move call returns.
     - Example: `tx.moveCall({ target: '0x2::devnet_nft::mint', arguments: [tx.pure(name), tx.pure(description), tx.pure(image)] })`
 - `tx.makeMoveVec({ type, objects })` - Constructs a vector of objects that can be passed into a `moveCall`. This is required as there’s no way to define a vector as an input.
     - Example: `tx.makeMoveVec({ objects: [tx.object(id1), tx.object(id2)] })`
@@ -108,7 +108,7 @@ tx.transferObjects([mintMany[0], mintMany[1]], tx.pure(address));
 
 ## Use the gas coin
 
-With Programmable Transactions, you’re able to use the gas payment coin to construct coins with a set balance using `splitCoin`. This is useful for Sui payments, and avoids the need for up-front coin selection. You can use `tx.gas` to access the gas coin in a transaction, and is valid as input for any arguments.
+With Programmable Transactions, you’re able to use the gas payment coin to construct coins with a set balance using `splitCoin`. This is useful for Sui payments, and avoids the need for up-front coin selection. You can use `tx.gas` to access the gas coin in a transaction, and it is valid as input for any arguments, as long as it is used [by-reference](../build/programming-with-objects/ch2-using-objects.md#pass-objects-by-reference). Practically speaking, this means you can also add to the gas coin with `mergeCoins` and borrow it for Move functions with `moveCall`.
 
 You can also transfer the gas coin using `transferObjects`, in the event that you want to transfer all of your coin balance to another address.
 
@@ -231,4 +231,4 @@ const sponsoredTx = Transaction.fromKind(kindBytes);
 sponsoredTx.setSender(sender);
 sponsoredTx.setGasOwner(sponsor);
 sponsoredTx.setGasPayment(sponsorCoins);
-```
+```